Communications plugs and patch cords with mode conversion control circuitry

Abstract

Patch cords include a communications cable that has first through eighth conductors that are arranged as four twisted pairs. A TIA 568B type plug may be attached to the cable. This plug includes a housing that receives the cable and first through eighth plug contacts that include plug contact regions that are substantially aligned in a row in numerical order. The plug further includes a printed circuit board that has first through eighth conductive paths that connect the first through eighth conductors to the respective first through eighth plug contacts. A first portion of the first conductive path and a first portion of the second conductive path are routed as a transmission line, and a first portion of the sixth conductive path is routed therebetween.

That which is claimed is: 
     
       1. A patch cord comprising:
 a communications cable that includes at least first through eighth conductors, wherein the fourth and fifth conductors are twisted together to form a first twisted pair, the first and second conductors are twisted together to form a second twisted pair, the third and sixth conductors are twisted together to form a third twisted pair, and the seventh and eighth conductors are twisted together to form a fourth twisted pair; and 
 a plug that is attached to the communications cable, the plug comprising:
 a housing that receives the communications cable; 
 first through eighth plug contacts that include plug contact regions that are substantially aligned in a row in numerical order; 
 a printed circuit board that is at least partly within the housing, the printed circuit board including first through eighth conductive paths that connect the first through eighth conductors to the respective first through eighth plug contacts, 
 wherein a first portion of the first conductive path and a first portion of the second conductive path are routed as a transmission line, and 
 wherein a first portion of the sixth conductive path is routed between the first portion of the first conductive path and the first portion of the second conductive path. 
 
 
     
     
       2. The patch cord of  claim 1 , wherein the first portion of the first conductive path, the first portion of the second conductive path and the first portion of the sixth conductive path are all on the same side of the printed circuit board. 
     
     
       3. The patch cord of  claim 1 , wherein the first portion of the first conductive path and the first portion of the second conductive path are on a first layer of the printed circuit board, and the first portion of the sixth conductive path is on a second layer of the printed circuit board that is different than the first layer. 
     
     
       4. The patch cord of  claim 1 , wherein a first portion of the seventh conductive path and a first portion of the eighth conductive path are routed in side-by-side fashion as a transmission line, and wherein a first portion of the third conductive path is routed between the first portion of the seventh conductive path and the first portion of the eighth conductive path. 
     
     
       5. The patch cord of  claim 4 , wherein the third and sixth conductive paths cross over each other at least twice. 
     
     
       6. The patch cord of  claim 4 , wherein the third and sixth conductive paths form an expanded loop on the printed circuit board. 
     
     
       7. The patch cord of  claim 4 , wherein the first portion of the seventh conductive path, the first portion of the eighth conductive path and the first portion of the third conductive path are all on the same side of the printed circuit board. 
     
     
       8. The patch cord of  claim 4 , wherein the first portion of the seventh conductive path and the first portion of the eighth conductive path are on a first layer of the printed circuit board, and the first portion of the third conductive path is on a second layer of the printed circuit board that is different than the first layer. 
     
     
       9. The patch cord of  claim 1 , wherein the first portion of the sixth conductive path is configured to couple substantially equal amounts of energy onto the first portion of the first conductive path and the first portion of the second conductive path when a signal is incident on the sixth conductive path. 
     
     
       10. The patch cord of  claim 1 , wherein the first portion of the sixth conductive path that is routed between the first portion of the first conductive path and the first portion of the second conductive path comprises a differential-to-common mode crosstalk cancellation circuit that at least partially cancels the common mode crosstalk that is injected from the third plug contact onto the first and second plug contacts. 
     
     
       11. The patch cord of  claim 1 , wherein at least a portion of the differential-to-common mode crosstalk cancellation circuit is located on a front half of the printed circuit board that receives the first through eighth plug blades. 
     
     
       12. The patch cord of  claim 1 , wherein the first portion of the first conductive path is on a first layer of the printed circuit board and the first portion of the second conductive path is on a third layer of the printed circuit board that is different from the first layer, and the first portion of the sixth conductive path is on a second layer of the printed circuit board that is between the first layer and third layer. 
     
     
       13. The patch cord of  claim 12 , wherein the printed circuit board is a flexible printed circuit board. 
     
     
       14. The patch cord of  claim 13 , wherein the first portion of the first conductive path, the first portion of the second conductive path and the first portion of the sixth conductive path are generally vertically stacked. 
     
     
       15. A patch cord comprising:
 a communications cable that includes at least first through eighth conductors, wherein the fourth and fifth conductors are twisted together to form a first twisted pair, the first and second conductors are twisted together to form a second twisted pair, the third and sixth conductors are twisted together to form a third twisted pair, and the seventh and eighth conductors are twisted together to form a fourth twisted pair; and 
 a plug that is attached to the communications cable, the plug comprising:
 a housing that receives the communications cable; 
 first through eighth plug contacts that include plug contact regions that are substantially aligned in a row in numerical order; 
 a printed circuit board that is at least partly within the housing, the printed circuit board including first through eighth conductive paths that connect the first through eighth conductors to the respective first through eighth plug contacts, 
 wherein a first portion of the sixth conductive path is routed so that, when excited by a signal, it will couple substantially equal amounts of signal energy onto a first portion of the first conductive path and a first portion of the second conductive path. 
 
 
     
     
       16. The patch cord of  claim 15 , wherein the first portion of the sixth conductive path includes a first current carrying path that is positioned adjacent the first portion of the first conductive path and a second current carrying path that is positioned adjacent the first portion of the second conductive path. 
     
     
       17. The patch cord of  claim 16 , wherein the first portion of the first conductive path, the first portion of the second conductive path and the first portion of the sixth conductive path are all on the same layer of the printed circuit board. 
     
     
       18. The patch cord of  claim 16 , wherein the first portion of the first conductive path and the first portion of the second conductive path are between the first current carrying path of the first portion of the sixth conductive path and the second current carrying path of the first portion of the sixth conductive path. 
     
     
       19. The patch cord of  claim 17 , wherein the first portion of the first conductive path and the first portion of the second conductive path are on a first layer of the printed circuit board, and wherein the first portion of the sixth conductive path comprises a widened trace that is on a second layer of the printed circuit board that is different than the first layer. 
     
     
       20. The patch cord of  claim 15 , wherein the first portion of the sixth conductive path overlaps the first portion of the first conductive path and the first portion of the second conductive path. 
     
     
       21. The patch cord of  claim 15 , wherein the printed circuit board is a flexible printed circuit board. 
     
     
       22. The patch cord of  claim 16 , wherein the first current carrying path of the first portion of the sixth conductive path is vertically stacked with the first portion of the first conductive path and the second current carrying path of the first portion of the sixth conductive path is vertically stacked with the first portion of the second conductive path. 
     
     
       23. The patch cord of  claim 15 , wherein a first portion of the sixth conductive path is routed between the first portion of the first conductive path and the first portion of the second conductive path. 
     
     
       24. The patch cord of  claim 15 , wherein the first portion of the first conductive path is on a first layer of the printed circuit board, and the first portion of the sixth conductive path is on a second layer of the printed circuit board that is different than the first layer. 
     
     
       25. The patch cord of  claim 15 , wherein the third and sixth conductive paths cross over each other at least twice. 
     
     
       26. The patch cord of  claim 15 , wherein a first portion of the third conductive path is routed so that, when excited by a signal, it will couple substantially equal amounts of signal energy onto a first portion of the seventh conductive path and a first portion of the eighth conductive path. 
     
     
       27. The patch cord of  claim 1 , the plug further comprising an offending crosstalk capacitor that is configured to couple signal energy between the first conductive path and the sixth conductive path. 
     
     
       28. The patch cord of  claim 1 , the plug further comprising an offending crosstalk capacitor that is configured to couple signal energy between the first conductive path and the fourth conductive path. 
     
     
       29. The patch cord of  claim 15 , the plug further comprising an offending crosstalk capacitor that is configured to couple signal energy between the first conductive path and the sixth conductive path.